White-throated sparrows normally end their song with repeated triplets, but a new song ending in repeated double notes has been sweeping a population in Canada
Source:
https://www.newscientist.com/article/2247763-canadian-sparrows-are-ditching-traditional-songs-for-a-new-tune/?utm_campaign=RSS%7CNSNS&utm_source=NSNS&utm_medium=RSS&utm_content=home